# defined?$B$N5sF0(B

**URL:** <https://www.ruby-forum.com/t/defined-b-n5sf0-b/134877>\
**Category:** Development\
**Created:** [April 15, 2008, 9:34pm UTC](https://www.ruby-forum.com/t/defined-b-n5sf0-b/134877 "2008-04-15T21:34:10Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [April 15, 2008, 9:34pm UTC](https://www.ruby-forum.com/t/defined-b-n5sf0-b/134877/1 "2008-04-15T21:34:10Z")

</div>

e$B$k$S$-$A$G$9!#e(B

defined?e$B$N5sF0$K$D$$$F5$$K$J$j$^$9!#e(B

class Object  
def p1  
p self; self  
end  
alias p2 p1  
end

defined? 1.p1 # =\> “method”  
defined? 2.p1.p2 # =\> “method”  
defined? [10].each # =\> “method”  
defined? [20].each{|x| p x} # =\> “expression”

# \>\> 2

# \>\> 20

e$B!Ve(Bdefined?  
2.p1.p2e$B!W$N\>l9g!"!Ve(B2.p1e$B!W$,I\>2A$5$l$k$N$O;EMM$G$9$+!)e(B

e$B$^$?!"%V%m%C%/IU$-%a%=%C%I8F$S=P$7$Oe(B"method"e$B$G$O$J$/$Fe(B"expression"e$B$K$J$j$^$9!#e(B  
e$B$7$+$b\<0$=$N$b$N$rI\>2A$7$F$$$^$9!#$3$l$O0U?^$7$?;EMM$G$9$+!)e(B

Ruby 1.8e$B!"e(BRuby 1.9e$BAPJ}$G$bF1$87k2L$G$9!#e(B